This object indicates the reason for which a port can
be allowed to toggle between up and down states.
linkFailure (1) - physical link failure.
trustSecViolation (2) - Cisco Trusted Security violation.
bitErrorRate (3) - bit error rate threshold exceeded.
signalLoss (4) - link failure due to loss of signal.
syncLoss (5) - link failure due to loss of sync.
linkReset (6) - link failure due to link reset.
creditLoss (7) - link failure due to excessive credit
loss indications.